Beta-Glucans: A Safe Bet for Health

Christine M. Palumbo, M.B.A., R.D.

You've probably heard about the benefits of soluble fiber -- it can help you maintain healthy cholesterol levels, regulate your bowel motility, and even reduce your risk for diseases like heart disease and certain cancers. And now, promising research on beta-glucans, a type of soluble fiber, helps explain why incorporating it into your diet could be beneficial.

Naturally occurring in certain foods, beta-glucans are branches of glucose molecules that can't be broken down into energy by human digestive enzymes because of their biochemical shape. Upon reaching the intestine, beta-glucans become a gel-like substance that slows the progress of food through the gastrointestinal tract and binds to dietary cholesterol, preventing it from being absorbed and lowering blood cholesterol levels. The Natural Standard Database, a website that investigates health claims of foods and herbs, reports that studies show about 3 grams/day can reduce cholesterol levels and aid blood sugar control in type 2 diabetes. Evidence suggests that up to 15 grams/day is safe.

More possible beta-glucan benefits include improved endothelial (blood vessel) function in cardiovascular disease, enhanced immune response, weight loss, anti-cancer activity, and wound healing. For example, topical applications of beta-glucan instead of surgical dressings have proven useful in treating burn victims. And in a January 2007 study published in International Immunopharmacology, oral beta-glucans seemed to stimulate monocytes, a type of cell produced by the body when the immune response is activated, in women with breast cancer. Since immune response can be compromised during cancer treatment, this function is of particular interest. Further research is needed to clarify these benefits.

You might not realize it, but you're probably already eating beta-glucans. Found in yeast, oats, barley, and some mushrooms, beta-glucans appear at varying levels and are categorized by terms that describe their chemical structure. In yeast and mushrooms, the branched links occur between the first and third or sixth carbon in the molecule, denoted as "beta-1,3 or 1,6 glucan," respectively. In oats and barley they are between the first and third or fourth carbon, written as "beta-1,3 or 1,4 glucan." Many supplements that contain beta-glucans have these numbers listed on the bottle, and some evidence suggests that the type made from yeast is more biologically active. For an added bonus, the foods that naturally supply beta-glucan are also good sources of important nutrients.

Beta-glucan in Foods

These sources provide about 3 grams of beta-glucan. Research indicates beta-glucan is not affected by cooking.

1/4 cups uncooked (or 1 cup cooked) pearl barley

1 1/2 cups uncooked (or 6 cups cooked) rolled oats

3 1/2 cups raw mushrooms (shitake, oyster, abalone)

Available in dietary supplements in varying amounts

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